scholarly journals Effects of surface morphology on thermal contact resistance

2011 ◽  
Vol 15 (suppl. 1) ◽  
pp. 33-38 ◽  
Author(s):  
Haiming Huang ◽  
Xiaoliang Xu
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Contact Resistance ◽  
Contact Area ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Average Height ◽  
Morphology Effect ◽  
Linear Manner ◽  
Nominal Contact Area

The thermal contact resistance is common in aerospace industry, nuclear reactors and electronic equipments. The work addresses a new scheme for determining the thermal contact resistance between a smooth surface of a film and a rough surface of a metal specimen. The finite element method was used as a tool to explore the surface morphology effect on the thermal contact resistance while the temperature of the contact surface was determined by a regression method. According to the results developed, the temperature on the contact surfaces linearly drops with the increasing average height of surface roughness and nonlinearly drops with the increasing ratio between non-contact area and nominal contact area. On the other hand, the thermal contact resistance increases linearly with increases in the average height of the surface roughness. What?s more, the thermal contact resistance increases in a non-linear manner as the ratio of the non-contact area to the nominal contact area is increasing.

Thermal Contact Resistance at a Metal Foam-Solid Surface Interface

2011 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Scott Hsieh ◽  
Majid Bahrami
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Effective Thermal Conductivity ◽  
Contact Area ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Metal Foams ◽  
Real Contact Area ◽  
The Real ◽  
Real Contact

Accurate information on heat transfer and temperature distribution in metal foams is necessary for design and modeling of thermal-hydraulic systems incorporating metal foams. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance (TCR) associated with the interface between the metal foams and adjacent surfaces/layers. In the present study, a test bed that allows the separation of effective thermal conductivity and thermal contact resistance in metal foams is described. Measurements are performed in a vacuum under varying compressive loads using ERG Duocel aluminum foam samples with different porosities and pore densities. Also, a graphical method associated with a computer code is developed to demonstrate the distribution of contact spots and estimate the real contact area at the interface. Our results show that the porosity and the effective thermal conductivity remain unchanged with the variation of compression in the range of 0 to 2 MPa; but TCR decreases significantly with pressure due to an increase in the real contact area at the interface. Moreover, the ratio of real to nominal contact area varies between 0 to 0.013, depending upon the compressive force, porosity, and surface characteristics.

scholarly journals How the Skin Thickness and Thermal Contact Resistance Influence Thermal Tactile Perception

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 87 ◽  
Author(s):  
Congyan Chen ◽  
Shichen Ding
Keyword(s):  
Surface Roughness ◽  
Contact Resistance ◽  
Thermal Model ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Experimental Studies ◽  
Tactile Perception ◽  
Skin Thickness ◽  
Temperature Profiles ◽  
Thermal Perception

A few experimental studies on thermal tactile perception have shown the influence of the thermal contact resistance which relates to contact surface roughness and pressure. In this paper, the theoretical influence of the skin thickness and the thermal contact resistance is studied on the thermal model describing the temperature evolution in skin and materials when they come in contact. The thermal theoretical profile for reproducing a thermal cue for given contact thermal resistance is also presented. Compared to existing models of thermal simulation, the method proposed here has the advantage that the parameters of skin structure and thermal contact resistance in target temperature profiles can be adjusted in thermal perception simulation according to different skin features or surface roughness if necessary. The experimental results of surface roughness recognition were also presented.

Experimental Investigation of Contact Resistance Across Pressed Lead and Aluminum Contact in Vacuum

2000 ◽  
Author(s):  
Xiao Ma ◽  
Jamil A. Khan ◽  
Curtis A. Rhodes ◽  
Allen Smith ◽  
L. Larry Hamm
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Cooling Water ◽  
External Pressure ◽  
Interface Temperature ◽  
Pressure Surface ◽  
Increasing Temperature

Abstract In a proposed nuclear application (production of Tritium using an accelerator, Accelerator Production of Tritium (APT)) lead is proposed to be used as a shield in the blanket module. This lead will be encased in aluminum cladding. The energy transfer rate from the lead to the cooling water will be a function of the thermal contact resistance (TCR) between lead and aluminum. Presently, data for contact resistance for this application does not exists in the literature. An experimental investigation has been conducted to determine the thermal contact resistance between lead and aluminum in vacuum. In this study we investigate the effect of pressure, surface roughness and interface temperature on the contact resistance. The experimentally determined range of contact resistance was found to be from 3.74×10−4K-m2/W to 11.45×10−4K-m2/W at 100°C∼200°C under 120∼370psi (0.827∼2.551MPa). The contact resistance increases to 168×10−4K-m2/W at small external pressure of 2.0∼3.9psi (0.013∼0.027MPa). The contact resistance decreases with increasing in contact pressure. Interface temperature and surface roughness do not affect the contact resistance significantly. There is a slight increase in contact conductance with increasing temperature. The experimental results provide contact resistance data, which should be a good reference for the APT design evaluation.

An analytical model of thermal contact resistance based on the Weierstrass—Mandelbrot fractal function

2010 ◽  
Vol 224 (4) ◽  
pp. 959-967 ◽  
Author(s):  
S Jiang ◽  
Y Zheng
Keyword(s):  
Contact Resistance ◽  
Surface Topography ◽  
Contact Area ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Fractal Model ◽  
Design Guidelines ◽  
Real Contact Area ◽  
Fractal Function ◽  
Conduction Theory

A fractal model for analysing the thermal contact resistance (TCR) of rough surfaces is presented; it is based on the classical heat conduction theory and fractal geometry for the surface topography description, elastic—plastic deformation of contacting asperities, and size-dependent constriction resistance. Relations for the TCR in terms of contact load are obtained for heat conductive surfaces with known material properties and surface topography. With the real contact area being approximately 1 per cent of the apparent contact area or less, the microcontact area distribution has a dominant influence on the TCR. Useful design guidelines for heat contacts are extracted from the numerical results. The analytical results agree well with previous experiments.

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